Positivism and logical empiricism in the 19th century

the term positivism derived from Earl of August. For his critical work, however, he can be considered a Hume like the first great positivist. He underlined the impossibility for deductive reasoning to produce factual assertions, since deduction takes place and affects a second level, that of concepts.

Positivism and logical empiricism

The development of the term positivism it was, however, incessant. The basic statements of positivism are:

1) That all knowledge of the facts is based on “positive” data drawn from experience. – that reality exists, the opposite belief is called solipsism.

2) Beyond the realm of facts there is pure logic and mathematics, Recognized by Scottish empiricism and especially by Hume as belonging to the “relation of ideas”.

At a later stage of positivism, the sciences thus defined acquire a purely formal character.

Mach (1838-1916)

He states that all factual knowledge consists of conceptual organization and elaboration of data from immediate experience. Theories and theoretical conceptions are only instruments of prediction.

Furthermore, theories can change, as long as the observational facts maintain empirical regularities and form a solid (unchanging) foundation for scientific reasoning. Positivist philosophers have radicalized empiricist anti-intellectualism, maintaining a radical utilitarian view of theories.

Avenarius (1843-1896)

He developed a biologically oriented theory of knowledge which greatly influenced American pragmatism. Just as adaptation needs develop organs in organisms – Lamarckism – so knowledge develops theories for the prediction of future conditions.

The concept of cause is explained in terms of the regularity observed in the sequence of events, Or as a functional dependence between observable variables. Causal relations are not logically necessary, they are only contingent and determined by observation and above all by experimentation and inductive generalization -Hume-.

Many scientists of the twentieth century, following the path traced by Mach, to which is added the influence of certain “ philosophers of mathematics ” such as Whithead, Russell, Wittgenstein, Frege, etc., more or less agglutinated unanimously around the positivist problem of the legitimacy of scientific theories.

Russell says, “Either we know something independent of experience, or science is a pipe dream.”

Some philosophers of science, known as the group of Circle of Vienna, established the principles of logical empiricism:

1. First, they believed that the logical structure of certain sciences could be specified without regard to their content.

2. Second they established the principle of verifiability, According to which the meaning of a proposition must be established by experience and observation. In this way, ethics, metaphysics, religion and aesthetics were excluded from all scientific consideration.

3. Third, they proposed a unified doctrine of science, While there were no fundamental differences between physics and biological sciences, or between natural sciences and social sciences. The Vienna Circle reached its peak during the pre-WWII period.


Another group of inductivists, of different orientation – among them those of influence Marxist, Which is known as Frankfurt School– are the conventional, Who argue that the major discoveries of science are fundamentally inventions of new and simpler classification systems.

The fundamental features of classical conventionalism -Poincar- are therefore decision and simplicity. They are, of course, also anti-realistic. In terms of Karl Popper (1959, p. 79):

“The source of conventionalist philosophy seems to be the surprise at the austere and beautiful simplicity of the world as revealed in the laws of physics. The conventional (…) treat this simplicity as our own creation … (Nature is not simple), only the “laws of nature” are, and these, support the conventional, are our creations and our inventions, our arbitrary decisions and our conventions. “

Wittgenstein and Popper

Other forms of thought soon opposed this form of logical empiricism: WittgensteinBut also positivist, faces the verificationist positions of the Vienna Circle.

Wittgenstein argues that verification is unnecessary. What the language can communicate to the “sample” is a picture of the world. For logical positivism inherited from Wittgenstein, logical formulas say nothing about the meanings of the propositions, but simply show the connection between the meanings of the propositions.

The fundamental answer will come from the falsificationist theory of Popper, Which holds the impossibility of an inductive probability with the following argument:

“In a universe that contains an infinite number of distinguishable things or spatiotemporal regions, the probability of any universal (non-tautological) law will be zero.” This means that increasing the content of an instruction decreases its probability, and vice versa. (+ Content = – probability).

To resolve this dilemma, he suggests trying to falsify the theory, seeking proof of the rebuttal or counterexample. Moreover, he proposes a methodology purely deductivist, in fact negative hypothetico-deductive or falsificationist.

In reaction to this approach, a number of emerging theorists who criticize logical positivism – Kuhn, Toulmin, Lakatos and even Feyerabend – although they differ on the nature of the rationality manifested by scientific change. They defend notions such as scientific revolution, as opposed to progress – Kuhn – or the intervention of irrational processes in science – the anarchist approach of Feyerabend.

Popper’s heirs now congregate under the Critical rationalism, In a last effort to save science, theory and the notion of “scientific progress”, which they do not do without difficulty, by proposing as alternatives, among others, the establishment of rival research programs, defined by their heuristics, and that they compete with each other.

The difficulties of logic models applied to the methodology of science could therefore be summarized as follows:

The induction of the theory, from particular data, was already clearly unjustified. A deductivist theory will not work because there is no general insurance principle from which the deduction can be deduced. A falsificationist view is inappropriate because it does not reflect scientific practice – scientists do not operate in this way, abandoning theories, when they present anomalies.

The result appears to be a skepticism widespread in terms of being able to distinguish between valid theories and ad hoc theories, so that it usually ends up appealing to history, i.e. the passage of time as the only sure method, or the less with certain guarantees, to judge the suitability of the models – another form of conventionalism.

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